Sound absorbent translucent building block



March 21, 1961 A. w. FRIEND 2,975,853

SOUND ABSORBENT TRANSLUCENT BUILDING BLOCK Filed Nov. 7, 1957 4Sheets-Sheet l Fig.4 *1

INVENTORI ALBERT W. FRIEND ATTYS.

March 21, 1961 A. w. FRIEND 2,975,853

SOUND ABSORBENT TRANSLUCENT BUILDING BLOCK Filed Nov. 7, 1957 4Sheets-Sheet 2 v v v v v v v v v v v (FREQUENCY m was FE/P JECO/YD)MENTOR: ALBERT W. FRIEND ATTYS.

March 21, 1961 A. w. FRIEND SOUND ABSORBENT TRANSLUCENT BUILDING BLOCKFiled Nov. 7, 1957 4 Sheets-Sheet 3 INVENTORZ ALBERT W. FRIEND ATTYS.

March 21, 1961 A. w. FRIEND 2,975,853

SOUND ABSORBENT TRANSLUCENT BUILDING BLOCK Filed Nov. 7, 1957 4Sheets-Sheet 4 INVENTORI ALBERT W. FRIEND BY WW ATTYS.

United States Patent "ice .SOUNDABSORBENT TRANSLUCENT BUILDING BLOCKAlbert W. Friend, 1334 Montgomery Ave., Narberth, Ia.

Filed Nov. 7, 1957, Ser. No. 694,959

19 Claims. (Cl. 18133) This invention relates to a translucentacoustical structure for use in building. The invention concerns abuilding block which may be made of incombustible material. It may bemade to pass or seal out air or other vapors, and it may be made totransmit essentially all rays of light or to transmit some and rejectothers. Additionally, it may be made essentially transparent oressentially translucent, and may incorporate known heat insulatingstructure, if desired.

In the prior art much attention has been devoted to room boundingmaterials capable of sound-proofing or acoustical damping. Particularemphasis has been directed to ceiling covering materials, but buildingmaterials of other types have also been sound proofed. Translucentbuilding materials, however, such as glass blocks, by their very naturehave proved among the most difficult materials to sound proof, and thosematerials of this type which are currently available continue to havethe objectionable property of being highly reflective of sound. Becauseof their tendency to produce acoustical echoes and other undesirableeffects, translucent building materials have been rejected for jobs forwhich they might otherwise be well suited.

My present invention is directed to a number of modifications ofbuilding blocks or tiles, or the like, having both light-transmittingand acoustic-absorbing qualities. These structures preserve thedesirable features of mechanical strength and pleasing appearance. Infact some of. the constructions proposed in accordance with my presentinvention lead to unusual and highly desirable means of varyingappearance including color, texture and light transmission qualities.

Specifically, in accordance with the present invention,

there is provided a translucent sound-absorbent building block whichcomprises pieces of solid translucent material bonded together toprovide a porous sound-absorbent yet solid unit. The material employedmay be of irregular size and shape or irregular in one respect and notthe other. Alternatively, the materials bonded together may be ofregular size and shape, and in many cases may even provide essentiallyparallel passages therethrough. One form of the present inventionemploys a plurality of elongated discrete translucive elements assembledgenerally parallel to one another. These elements may be rods in somecases, and may be tubes in others. In still other cases, there might bea combination of rods and tubes, all arranged parallel to one another.Preferably; the building block is provided with some sort of solidframing portion, and the porous portion is located within the frame. Theframe may be simply a rectangular enclosure or it may be a relativelysolid member having a number of openings in it. In the latter case, thenature and size of the openings in many instances will to some extentdetermine the type of material used within. the opening. Additionally,the block may be completely open from one side to the other, and hencefreely permit the passage of gases and vapors, or they may be closedand, in fact, in some instances may be 2,975,853 Patented Mar. 21, 1961closed by a double wall which may even be evacuated or pressurized forinsulating purposes.

The present invention also contemplates the method of forming certaintranslucent sound-absorbent blocks comprising certain simple methodsteps including a step of bonding or fusing together the pieces makingup the blocks.

For a better understanding of the present invention, reference is madeto the following drawings in which:

Fig. 1 is a perspective view of a typical block of the present inventionfrom its interior surfaces;

Fig. 2 is a perspective view of the same block from the exteriorsurface;

Fig. 3 is a detail of the block of Fig. 1 in which tubular elements areemployed;

Fig. 4 is a view of part of an interior surface of a wall employingbuilding blocks constructed in accordance with the present invention;

Fig. 5 is the exterior surface of the wall of Fig. 4;

Fig. 6 is a detail view similar to that of Fig. 3 but showing a modifiedform in which greater fusion has taken place between the elements in astructure which may completely do away with the frame;

Fig. 7 is a partial sectional view of one method of construction of theblock of Figs. 1 and 2;

Fig. 8 is a sectional view similar to Fig. 7 but showing a modified formof block made with tubular elements;

Fig. 9 is another sectional view showing still another modified form ofthe block made of tubular elements;

Fig. 10 shows a front elevational view of the block of Figs. 1 and 3using tubular elements in its construction;

Fig. 11 is a modified form of the block shown in Fig. 8 in which theends of the tubes are closed;

Fig. 12 is a block which may be similar to the blocks of Figs. 7-9 butemploys rods instead of tubes;

Fig. 13 shows a variation of the arrangement of Fig. 11;

Fig. 14 shows still another variation having openings in solid blockmaterial;

Fig. 15 shows a modified form of any of the blocks previouslyillustrated in which the individual discrete elements are not horizontalor parallel to some part of the framing means;

Fig. 16 shows another modification of the same feature which alsoprovides for diffusion surfaces on the block; P Fig. 17 is a detail viewof a portion of the structure of Fig. 18 is a graph illustrating dampingcharacteristics which might be expected of a typical block of the typedescribed;

Fig. 19 is a perspective view of a modified form of block;

Fig. 20 shows a modified form of a block of the general type of Fig. 19;

Fig. 21 shows a sectional view through the block of Fig. 19 or Fig. 20;

Fig. 22 shows still another modified form of block using sound absorbentmaterial of the type employed in Figs. 19 and 20;

Fig. 23 is a sectional view of the block of Fig. 22 on line 2323;

Fig. 24 shows in perspective a modified form of soundabsorbent materialfor insertion in the openings of the block of Fig. 20;

Fig. 25 shows in perspective a modified form of material for insertionin the block of Figs. 22 and 23;

Fig. 26 shows in perspective still another version of the presentinvention employing parallel plates;

Fig. 27 is a sectional view taken along line 27-47 of Fig. 26;

Fig. 28 is a perspective partially expanded view of the plate structureof the block of Fig. 26;

Fig. 29 shows in perspective a block employing plates in a form modifiedfrom the plates of Figs. 2628;

Fig. 30 is a detail taken from Fig. 29; and

Fig. 31 shows an individual element employed in the structure of Fig.29.

Referring to Figs. 1-3 of the drawings; a typical block made inaccordance with one embodiment of the present invention is illustrated.The detailed construction of the block is shown in the upper left handcorner of Fig. l which shows only the detailed part of the block in fulllines and the rest of the block in phantom. The detail arrangement ofelements of the structure can be seen in Fig. 3 to consist of a matrixof hollow tubular members preferably of translucent material such asglass. These tubular members are arranged within a hollow frame 11,which as shown may be square or of any other suitable shape andpreferably cast'of glass or other translucent material. The outer facesare flat in the sense that they are intended to provide faces to opposesimilar flat faces on other blocks over their entire length. It will beunderstood that there may be channeling or other discontinuities inthese faces without eliminating their general flatness. The frame isclosed at its external surface by a plate 12, usually of the samematerial as the frame, which, as seen in Fig. 2, may be provided with acorrugated light refracting external surface. The tubular members ofFig. 1 may be arranged in various patterns and, additionally, may becolored and so arranged that the colors form a pattern in the face ofthe blocks. Patterns in the blocks, in turn, make possible designs orother patterns in a wall, such as that shown in Fig. 4 illustrating adecorative design at an interior wall surface employing blocks which aremade of a composite of tubular glass pieces of two different colors. Theexternal surface of the wall may be seen by reference to Fig. 5. Thearrangement shown employs an assembly of the patterned glass blockswhich has the rows staggered so that only alternate rows provide avertical column. Other pattern arrangements are, of course, possiblewithin individual blocks or over the interior and/or exterior wallsurface.

It will be appreciated that a structure of the type shown in Figs. 1 to3 may be a composite of glass tubes which are preferably fused togetherin some manner. This may be done by placing them in a furnace, raisingthe temperature to a point of plasticity of the glass and permittingslight fusion and coalescence to occur. A different effect can beachieved by permitting greater fusion to occur which, however, mayrequire higher temperatures and require greater care in and control overthe process to assure the effect desired. Such a different effect may beseen in Fig. 6. The tubular members 10 may be assembled and separatelyheat treated, or may be placed in their frame 11 and treated in place.In some cases, a frame 11 may not be employed and may not be desirable,but a frame is intended to lend somewhat greater strength to thestructure as a whole and to provide a suitable surface for mortar inaccordance with techniques well known in the art. The material of theblocks is preferably glass, as previously suggested, although othertranslucent materials may be used. In particular, it is usuallydesirable to make the frame 11 of glass even if the internal structureshould be made of another material, such as certain plastic materials,for example, polyvinyl chloride products, or the like.

Fig. 7 shows a preferred internal construction of the block of Figs. 1-3wherein the tubular members are open at each end and are terminatedsomewhat short of the external face plate. The structure shown in Fig. 7may be modified as shown in Fig. 8 by extending the tubes all the way tothe back closure thereby closing their ends and achieving a differentacoustical effect.

Fig. 9 shows still another version where no back plate is employed. Thisconstruction will probably find fewer uses but might be employed in suchapplication as outdoor walls where it is not necessary to provide abarrier to wind and vapors yet it is desirable to pass a certain amountof light and at the same time to dampen sound.

Fig. 10 is a face view of the front of the building blocks shown inFigs. 7, 8 and 9 illustrating that the ex-- ternal appearance of thesurface of the block used for interior walls is unchanged no matterwhich of the Figs. 7-9 is employed. This pleasing optical effect istherefore possible with a wide range of acoustical effects.

Refer-ring to Figs. 11 and 13, there is shown a modified form ofstructure in which tubes 10 are made with closed ends in the form ofvery deep cups. This will have the effect of closing off some of thepassages through the block and leaving others open so that a mixedresonance effect is obtained. Open passages occur between the varioustubes. Fig. 13 illustrates in greater detail a modified arrangement ofelements of the type employed in Fig. 11 with passages between the tubesclosed at the same end as the closed ends of the tubes.

Fig. 12, by contrast, shows the use of rods 14 as opposed to tubes. Thisconstruction may assume the form of any of the constructions of Figs.7-9.

Fig. 14 illustrates still another arrangement wherein openings areprovided periodically in the face of a block and may be formed by fusionof glass tubes, by casting the block or by boring.

The rod or tube elements of Figs. l-4 all are arranged to enhance lighttransmission by providing light guiding paths of transparent materialfrom one side to the opposite side. The light may enter the rods ortubes at one end and emerge from the other, being confined at thetransparent-materialato-ainboundary surfaces because of the ratio ofrefraction indices of the transparent material and air which causesalmost total reflection at these surfaces, at large incident lightangles. This effect minimizes light scattering and reflection back tothe side of light entry. The application of tubes or rods in this mannerpossesses a definite advantage in greater light transmission as comparedwith the use of cavities in glass building blocks filled with randomlyoriented strands of Fiberglas or closely packed glass powder inembodiments to be later described.

In most applications where the incident light comes down at an anglefrom the sky, it is of advantage to bevel the surface on which lightimpinges to as much as 45 as shown in Fig. 7. If plate 12 does notpresent repetitively beveled ridges, as shown, the outer ends of therods or tubes may be beveled to reduce the light reflection at theincident surfaces and so to increase the light transmission just as doesthe horizontally ridged surface of back plate 12.

In a variation of the above light directing means, the rods or tubes maybe tilted downward as they progress inward through the block, as shownin Figs. 15 and 16. Their upturned outer ends will more effectivelyreceive the incoming light and they will transmit it through theirentire lengths with a minimum of reflections, and hence with maximumefliciency. Under such conditions a still further improvement may bemade by beveling the inward ends of the rods or tubes, so that theirlower edges are undercut, to refract the light at a higher angle, asshown in Fig. 17. Alternately, the ends may he randomly oriented orrounded to scatter the inward propagating light in all directions.

Fig. 16 also shows a modified frame arrangement wherein frame member 12has beveled surfaces to carry the tubular members.

If wall sections (blocks or panels) are formed as shown in Fig. 10, forexample, by fusing or cementing together aggregates of parallel shortlengths of glass or plastic tubing, the wall surface formed by the endsof the tubes is perforated bythe tube bores and also by the aperturesbetween the outside surfaces of the tubes. An incident sound wave issubdivided into a group of individual waves which travel through thetubular passages, and a wave reflected back into space; 'The wavestransmitted in the passages are attenuated. If the passages are open tothe air on the opposite side, to allow air to pass through the wall,then some of the remaining sound energy will be propagated into the airon that side and some will be reflected and will return through thetubular passages toward the first side, being attenuated in the process.If the opposite side is closed by a solid panel or by closure of theindividual tubular passages, then the remaining sound energy will bealmost entirely reflected, except for a small amount of energytransmitted through the solid material of plate 12. This reflectedenergy will likewise be attenuated in the passages. In either of thesewall types the remaining sound energy reflected back, and havingsurvived two passages through the tubes will be partially transmittedback into the air on the side of original incidence, to add vectoriallyto the original reflected wave. Due to the discontinuity a barriereffect may be present causing a small portion to pass back into thepassages, adding to any new incident energy in the passageways, and soon through a new cycle. These same processes take place in any materialof this type regardless of its light transmissive properties.

Fig. 18 is a chart showing how the regular hollow or tubular elements ofFigs. 1-17 tend to damp sounds sele ctively.

Cylindrical tubes of 0.025 inch inside diameter or less are effectiveattenuators within the audible sound range, for. instance, if they areof lengths exceeding possibly one to 'two inches, or more. An example ofacoustic energy attenuation in such a small tube of 0.025 inch insidediameter and 4.5 inches length is plotted as a function of frequency inFig. 18. It will be noted that the attenuation increases from 2.5decibels at 100 cycles per second to 47.5 decibels at 7200 cycles persecond. This is for a single'transmission. When'reflection's occur atthe far end of such tubes the attenuation is doubled.

If greater low frequency sound transmission attenuation or soundabsorption is required the value of the diameter of the openings must bemade quite small or their tubular lengths must be increased. Aflattening or' irregularity of surface of the tubular passages is alsouseful in increasing acoustic energy absorption. This eifect is producedby the mounting together of parallel cylindrical rods or tubes, as inFigs. or 12, by the action of the spaces between the outer surfaces astubes with convex inner surfaces formed by the outsides of adjacent rodsor tubes.

The advantage of the structures. of Figs. 1-17 (and Figs. 26-31) of myinvention is the combination of excellent acoustical absorptionproperties with maximum transmission of light incident from the sideopposite the sound incidence (the second side), while also providinggreat mechanical strength, rigidity, fire resistance, and freedom fromthe need for added surface decoration or protection from not and fungusattack. All these are provided by the structures of Figs. 1-17 whenglass or other vitreous substance is the sole material and when alltubes or rods are solidly fused together. If translucent plastics areused one or more of these properties may be deteriorated, depending uponthe specific plastic used, but the material may be more resistant tomechanical shock and more flexible.

The tube or rod structures of Figs. l-l7 may be produced by cutting tolength the required small size lengths of tube or rod of glass orplastic, assembling them into the desired size units, possibly with oneor more outer covering plates, and heating the assembly sufficiently tolightly fuse the whole together. Flame heating may be used to seal oneend of the tube or rod array passages, instead of using a cover plate.As an alternate method of production, a group of coalescing rods ortubes may be simultaneously drawn, and may be sawed into the desiredshort lengths after cooling to harden.

Other modified forms of the present invention are shown in Figs. 19-23.These forms in their various embodiments may have superior soundabsorption characteristics but poorer light transmission properties thanthose of Figs. 1-17. In these arrangements discrete particles, strandsor fabric surfaces may be fused together in a highly porous form withinopenings in framing solid blocks. Where porous material in discretepieces is employed, the pieces may be small in size or may be of thesize of marbles or larger. The particles may be uniform in size andshape or may be varied in one respect or the other. The porous materialmay be formed, for example, of glass powder beads, or granules solidlypacked and slightly sintered to cause it to coalesce into a massmechanically strong but still porous. Blocks of this form have generallypoorer light transmission properties than other types but can beproduced at low cost. In the actual structure, the divided material 20within the frame 22 fills the block to the back plate 21. The material.20 may be precast in a block and inserted, but preferably is firstpacked in place and then fused or sintered by some process bonding theparticles together but leaving openings throughout the structure.

The openings in the block of Fig. 20 differ in shape and size from thoseof Fig. 19, but in other respects are similar. This, of course,necessitates the use of porous material plugs 20' of appropriate sizeand shape. However, as can be seen from Fig. 21, the vertical crosssection of both blocks of Figs. '19 and 20 is essentially the same.

The same remarks are true of the block of Fig. 22 in which the frame 22"is of a different shape and provides generally cylindrical holes for theinsertion of plugs of sound absorbent material 20" which, as may be seenin Fig. 23, extends clear through the block to back plate 21".

Instead of the porous plugs formed from discrete particles, fabric-likematerials of Fiberglas, or other fibres, thin films or bats of glasswool or the like, may be inserted after being rolled as shown in Fig.24, or otherwise suitably formed for the openings in the block 22 ofFig. 20, or as shown inFig. 25 for the openings in the block 22 of Fig.22. I

Still another form of the present invention is shown in Figs. 26 through30. Here the rod elements may be replaced by an array of very thinparallel flat glass or plastic sheets spaced very close together (about0.005 to 0.025 inch). These versions, in turn, have variations amongthemselves as shown, respectively, by Figs. 26-28, and Figs. 29-31. Asseen in Fig. 26, the block consists of a frame 30 having a back plate31. The frame is filled with generally vertically arranged glass plates32, spaced apart by glass spacers 33 adjacent opposite ends of theplates as shown in Fig. 28. The plates are preferably arrangedvertically to give maximum strength in the direction of the highestgradient load, but may be arranged horizontally for other purposes.

Since the use of spacers constitute a tedious assembly job where smallquantities do not justify automatic assembly, the form of this versionof the invention as shown in Figs. 29-31 will be preferred. In thisversion no spacers are required since the plates 32' are corrugated, asshown in Fig. 31. The arrangement of the plates 32 to define openingswithin the frame 30' is shown in Fig. 30. The plates in either versionmay extend against or be spaced from the back plate 31.

The assemblies of Figs. 26-31 may be made of glass or similar vitreousmaterials (or of plastic) and fused together (or cemented) to form arigid building block of very large acoustic absorption.

It will be appreciated that any versions of the present inventionemploying back plates may be modified to include a dead space betweenthe back plate of the block and an intermediate plate which is placedwithin the block for the purpose of insulation. Shch a cavity may y beevacuated or use dead air or some other insulating medium.

Other modifications within the scope of the claims, including thevarious common expedients used by the trade in connection with glassblocks or tiles, are intended to be within the scope of the presentinvention.

I claim:

1. A translucent building block having peripheral hearing faces andfront and rear exposed sides, said block having sound attenuatingopenings extending inwardly from at least one side thereof, and saidblock being otherwise solid throughout and capable of bearing load onits peripheral faces.

2. The translucent building block of claim 1 in which the materialforming at least a portion of the block is material which consists ofpieces so arranged relative to one another that they provide the soundattenuating openings between them.

3. The translucent building block of claim 2 in which the pieces arerandomly distributed and fused together.

4. The translucent building block of claim 2 in which the pieces arealongated in a direction extending between front and rear relative totheir thickness.

5. The translucent building block of claim 4 in which the pieces arefused together.

6. The translucent building block of claim 2 in which the pieces arefibrous.

7. The translucent building block of claim 1 in which the soundattenuating openings are provided in a portion of the block bounded by aframing portion which provides the peripheral bearing faces.

8. The translucent building block of claim 7 in which the material ofthe block within the framing portion is fibrous.

9. The translucent building block of claim 8 in which the fibers are ina fabric arranged to occupy the volume left by the framing portion.

10. The translucent building block of claim 7 in which the materialwithin the framing portion consists of a plurality of elongatedtranslucent elements assembled generally parallel to one another.

11. The translucent building block of claim 10 in which the elements aretranslucent rods.

12. The translucent building block of claim 10 in which the elements aretranslucent tubes.

13. The translucent building block of claim 12 in which the tubes areopen at both ends.

14. The translucent building block of claim 12 in which the tubes areopen at one end and closed at the other.

15. The translucent building block of claim 10 in which the elements aretranslucent plates.

16. The translucent building block of claim 15 in which the translucentplates are spaced apart one another by spacers.

17. The translucent building block of claim 15 in which the translucentplates are corrugated and so arranged that their corrugation createspace between them to form the sound attenuating openings.

18. The translucent building block of claim 7 in which the rear exposedside is completely closed by a solid translucent face.

19. The translucent building block of claim 2 in which there is a cavitybetween the assembly of pieces and the translucent member at the rear ofthe block.

References Cited in the file of this patent UNITED STATES PATENTS1,483,365 Mazer Feb. 12, 1924 1,878,409 Lyford Sept. 20, 1932 2,011,252Modigliani Aug. 13, 1935 2,105,174 Zimmerman et al I an. 11, 19382,484,003 Simison Oct. 4, 1949 2,596,659 DEustachio May 13, 19522,643,020 Dalton June 23, 1953 2,657,759 Creamer Nov. 3, 1953 2,714,816Pennell Aug. 9, 1955 2,870,857 Goldstein Jan. 27, 1959 FOREIGN PATENTS531,610 France Oct. 27, 1921 538,306 Great Britain July 29, 1941 723,621Great Britain Feb. 9, 1955 1,136,944 France Jan. 7, 1957

